People with chronic health conditions are being asked to do more and more to maintain their health. This chronic workload can negatively impact well-being, reduce adherence to treatment, and ultimately jeopardize long-term clinical outcome. Those with multiple chronic conditions (MCCs) are especially vulnerable to this treatment burden as they must often maintain an array of self-management activities for different conditions simultaneously. In order to find effective ways of relieving treatment burden in people with MCCs, we must first find ways to validly measure it. In an NIH-funded R21, we recently developed the first general (non-disease, non-treatment specific), multi-domain measure of treatment burden - the Patient Experience with Treatment and Self-care (PETS). While cross-sectional validation is nearing completion, the PETS still requires large- scale prospective validation to help determine its responsiveness and feasibility for use in multiple settings. Hence, our overall goal in this project is to conduct a comprehensive validation test of the PETS measure in three distinct settings: clinical research, performance measurement, and clinical practice. We will accomplish this by conducting three sub-studies over five years. The following specific aims will be pursued: Aim 1: Examine the validity of the PETS prospectively in a large cohort with MCCs. We will conduct a longitudinal survey study of a cohort of 600 people with MCCs identified from the Rochester Epidemiology Project, a medical records linked system for residents of Olmsted County, Minnesota. Aim 2: Derive, validate and assess feasibility of a PETS performance measure. Input from patients (30), nurses (10), and physicians (10) will be used to derive a shortened version of the PETS for performance measurement. This will be followed by a prospective test of the measure with 400 MCC patients half of whom will be recruited from primary-care practices of Minnesota's largest public safety-net hospital. Aim 3: Adapt and evaluate a clinical tool to assess treatment burden to aid care communication and planning for MCC patients. The PETS measure will be used to provide source content for an adaptation of an existing web-based tool for use by patients and clinicians at the point of care. Following a development phase involving input from patient and clinician discussion groups as well as derivation of the user interface, the tool will be evaluated for efficacy and feasibility i 80 MCC patients recruited from primary-care practices at two medical centers. This project will result in a set of robust, patient- and clinician-friendly measures and tools for assessing patient treatment and self-management burden in research, performance measurement, and practice applications. The project is consistent with the NINR's thematic focus on self-management and the Department of Health and Human Services vision of optimizing health and quality of life for individuals with MCCs.